The discussion turned on work on the Sabbath. The Father's work in maintaining and redeeming the world has continued from the creation until the present moment (ἕως ἄρτι): until now, not interrupted by the Sabbath.

And I work (κἀγὼ ἐργάζομαι)

Or, I also work. The two clauses are coordinated. The relation, as Meyer observes, is not that of imitation, or example, but of equality of will and procedure. Jesus does not violate the divine ideal of the Sabbath by His holy activity on that day. "Man's true rest is not a rest from human, earthly labor, but a rest for divine, heavenly labor. Thus the merely negative, traditional observance of the Sabbath is placed in sharp contrast with the positive, final fulfillment of spiritual service, for which it was a preparation" (Westcott).

John 5:16 And this was why the Jews were persecuting Jesus, because he was doing these things on the Sabbath.

John 5:18 This was why the Jews were seeking all the more to kill him, because not only was he breaking the Sabbath, but he was even calling God his own Father, making himself equal with God.

John 10:36 do you say of him whom the Father consecrated and sent into the world, 'You are blaspheming,' because I said, 'I am the Son of God'?

1 Thessalonians 2:13 And we also thank God constantly for this, that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.